GB/T 41143-2021Glossary of terms of instrumentation and control for nuclear power plants (English PDF)

3.1 Operational states

A general term for two states of normal operation and expected operation events.

3.2 Normal operation

The operation of a nuclear power plant within specified operating limits and conditions.

3.3 Design basis

The various operating conditions and events that are fully considered in accordance with established criteria in the design of structures, systems, components and equipment of a facility range of conditions so that the facility can withstand these conditions and events without exceeding regulatory limits.

3.4 Postulated initiating event; PIE

Hypothetical events identified during design that may lead to expected operational events or accident conditions.

3.5 Anticipated operational occurrence; AOO

Various operating processes that deviate from normal operation at least once during the operating life of a nuclear power plant;

Measures should be taken so that such events will not cause serious damage to items important to safety, nor will they lead to accident conditions.

3.6 Design basis event; DBE

A hypothetical initiating event used in the design to determine acceptable performance requirements for a structure, system or component.

3.7 Design basis accident; DBA

Hypothetical accidents leading to accident conditions in nuclear power plants.

Note 1. The nuclear power plant is designed according to established design criteria and conservative methods.

NOTE 2 The releases of radioactive material from these incidents were within acceptable limits.

3.8 Design extension conditions; DEC

Accident conditions that are considered in the design process according to the best estimation method and are not considered in the design basis accident.